1. Field of the Invention
The present patent application for industrial invention relates to a manufacturing process of a shoe provided with an internally waterproofed fabric upper, and a molding assembly to perform the manufacturing process.
Also if following the description specifically refers to boots, the scope of the invention extends to any type of shoe provided with closed or opened upper, such as Ballet flats or Dolly shoes, sandals, sabots, and like.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Known are boots composed of a rubber sole and a fabric upper fixed to the sole. In particular, the upper is provided with a structure that is similar to a sock. The upper is formed of a tubular section adapted to embrace the user's leg and of a base sack adapted to receive the foot and surround it completely. The bottom of the base sack must be exactly disposed in contact with the upper side of the sole. Generally fabric uppers are used, since this type of material can have any desired color and/or surface decoration, thus guaranteeing the aesthetic peculiarity of the boot provided with such an upper.
Nevertheless, a fabric upper is not intrinsically able to offer the self-support, resistance and waterproof properties that are compatible with the use of a boot, i.e. a type of footwear that is typically used in cold months with adverse weather conditions. For this reason, the fabric of such an upper is coated by applying an external layer of transparent or colored plastic material (preferably PVC) that, in addition to increasing the resistance and self-support properties of the upper, allows leaving the color and decoration of the fabric used to make the upper.
Such an operation is made with a special mold, which is normally formed of three cooperating parts.
The first part consists of a core that reproduces the user's leg and foot. The fabric upper to be coated with the plastic material is inserted on said core.
The second part consists of a mold die, which is preferably formed of two semi-shells, adapted to be tightened on the two sides of the core, which is already provided with the fabric upper.
The third part consists in a mold lid adapted to close the die, in contact with the bottom of the core and substantially with the bottom of the “sack” of the upper inserted on the core.
Transparent plastic material in fluid state is injected into the mold. In particular, such an injection is made by means of nozzles inserted through said lid. The plastic material injected by the nozzles penetrates between the fabric upper and the walls of the mold covering the entire surface of the upper.
After completing this step of the injection process, the lid is removed and replaced with a second lid, which is specifically adapted to mold the rubber sole directly under the bottom of the fabric upper, which is completely coated with the plastic material.
Such a technology is highly impaired by a significant drawback. The layer of transparent plastic material that consolidates externally on the fabric upper prevents the user from feeling the fabric and partially alters the visual perception of the color and/or decoration of the same fabric.
The impression generated by a boot manufactured according to the traditional technology is that the upper is directly made of a colored and/or decorated material, and not of fabric.
The purpose of the present invention is to provide a shoe with fabric upper that is waterproof and in the same time it is perceived as fabric both from the tactile and the visual viewpoint.